ZOOLOGY 



391 



remarkable ruminant, Speke's tragelaph (Limnotragus spekei), a creature 

 which inhabits the large swamps of the more tro})ical portions of the Uganda 

 Protectorate. The tragelaphs are a group of hollow-horned ruminants 

 incorrectly included under the designation of antelope. They are in reality 

 no more antelopes than they are oxen, and, as a matter of fact, are more 

 closely allied in origin to the last-named group. All hollow-horned 

 ruminants — oxen, tragela[)hs, capricorns, goats and sheep and antelopes — 

 are very closely allied in structure, but they might be more correctly 

 grouped than they are, in homogeneous divisions. The ca^jricorns, goats, 



241. BAKEK 8 ROAN ANTELOPE (HIPPOTRJCCS B.lKliRI 



sheep, and antelopes have one almost constant feature in the structure of 

 their horns. These are annulated with distinct rings of growth, which in 

 most instances develop into verv apparent transverse ridges. In the oxen 

 and tragelaphs there are but faint traces of these regular annulations, if, 

 indeed, there are any traces at all. The common ancestor of the oxen, 

 the tragelaphs, and the great group of ring-horned ruminants had short 

 triangular horns, the laminations of which may have taken the form of 

 regular rings of growth. The lowest existing type of ox — the anoa — has 

 horns nearly triangular in section. The early tragelaphs, like the nilghai 

 of India, also had triangular horns. Early in the history of the tragelaphs, 

 however, the horns in their upward growth began to take a spiral direction, 



